Methods:
Exploratory study, developed in 3 ophthalmology centers. Twenty-four DR patients (48 eyes) were recruited and classified in 2 groups: nonproliferative DR and history of diabetic macular edema (DME) in both eyes (OU), submitted to macular laser OU and anti-VEGF injection only in one eye (NPDR+DME, n=10); proliferative DR OU, treated with panretinal photocoagulation (PRP) OU and anti-VEGF injection only in one eye (PDR, n=14). Images were acquired with spectral-domain OCT Enhanced depth imaging protocol (Heidelberg Engineering-Germany). The line of retinal pigment epithelium/Bruch membrane complex and the line of scleral/choroid interface were marked manually in the 5 central B-scans, by two independent observers blinded to the diagnosis, using MATLAB software (The Mathworks, Natick, MA, USA). The medium CT in central macular area (1mm diameter) (CCT) and the CT in centrofoveal B-scan, measured in 500µm intervals, were obtained automatically.

Results:
Eyes treated with anti-VEGF showed a significant reduction of CCT (249.1±67.9µm versus 277.9±75.2µm, p<0.005) and subfoveal CT (255.2±75.5µm versus 285.3±83.9µm, p<0.05) compared with eyes, of the same patients, treated only with laser. In the analysis performed separately to each group, PRP eyes treated with anti-VEGF also showed a significant reduction of CCT, compared with eyes of the same group with laser treatment only (262.9±71.7µm versus 296.3±81.5µm, p<0.05). In NPDR+DME group the CCT was reduced in eyes with anti-VEGF therapy, without statistical significance (229.8±60.4µm versus 252.0±60.0µm). In both groups, there was no correlation between CT and the type of anti-VEGF agent or the number of injections. In PDR group, we verified a positive correlation between the number of PRP spots and CCT (R=0.041; p<0.05) and CT in 6 of the 13 measures in central B-scan.

Conclusions:
To our knowledge, this is the first analysis of the role of anti-VEGF therapy in the CT of DR patients. Eyes treated with anti-VEGF agents, compared with eyes of the same patients treated only with laser, seem to present a reduction in submacular CT evaluated by EDI OCT. PRP may improve submacular CT.